1. Field of the Invention
This invention relates to an endoscope device improved so that, when a treating tool is used, the irrigated amount within the channel may be sufficiently secured without making the diameter of the inserting part larger.
2. Related Art Statement
There is recently extensively used an endoscope wherein the elongated inserting part is to be inserted into a body cavity so that organs within the body cavity may be observed, a tissue within the living body may be taken out to diagnose particularly the affected part by using such treating tool as a forceps inserted through a channel as required and such various treatments may be made.
There are a soft endoscope wherein the inserting part is soft and curvable and a rigid endoscope wherein the inserting part is rigid and substantially linear.
A rigid endoscope of a type having a channel is shown, for example, in the publication of a West German utility model application laid open No. G 8119209.6. This is an endoscope wherein a tube of an oval cross-section is provided within an outer tube of a circular cross-section, an observing optical system and a conduit in which a probe is inserted are arranged within the tube of the oval cross-section and photoconductors are contained and arranged in hollow gaps enclosed with the outer peripheries of the above mentioned observing optical system and the conduit and the inner periphery of the tube of the oval cross-section.
An endoscope of a formation related with it is also shown in FIGS. 1 and 2. That is to say, in this endoscope 1, an optical system pipe 3 within which an observing optical system is provided and a channel 4 circular or semicircular in the cross-section and comparatively large in the diameter are inserted and arranged within an outer pipe 2 forming an inserting part and light guide fibers 5 for an illuminating optical system are inserted and arranged in hollow gaps enclosed with the outer peripheries of the above mentioned optical system pipe 3 and the channel 4 and the inner periphery of the outer pipe 2. This endoscope 1 is to be used as combined with a sheath 6.
Now, in the endoscope of the above mentioned prior art example, the observing optical system, illuminating optical system and channel are integrally incorporated within the outr pipe and therefore the diameter is larger by the thickness of this outer pipe. Therefore, in order to absorb the dimension of the thickness of this outer pipe, it is considered (i) to make the diameter of the sheath larger by that thickness, (ii) to make the diameter of the channel smaller by that thickness, (iii) to make the outside diameter of the observing optical system smaller by that thickness and (iv) to make the thickness of each pipe smaller by that thickness. However, in (i) above, the pain given to the patient will become larger by the outside diameter of the sheath made larger. In (ii) above, by the channel made smaller, the outside diameter of the usable treating tool will become smaller and therefore the effect of the treatment will reduce. In (iii), the capacity of the observing diagnosis will reduce. In (iv), the strength will reduce. There are such problems.
On the other hand, there is a problem that, if the cross-section of the channel 4 is circular as shown in FIG. 1, in a case a treating tool 7 is inserted into the channel 4, the space other than for the treating tool 7 within the channel 4 will become small and the amount of irrigation by using the space will reduce.
By the way, in the publication of a Japanese utility model publication No. 4786/1958 is disclosed an endoscope formed of an observing optical system, lamp, water discharging port and electrode inserting channel which are respectively independent. However, in this endoscope, the channel is of a circular cross-section and is arranged in the center of the endoscope, the clearance within the underside sheath is used as a water feeding path, therefore the diameter of the channel is restricted and no channel of a large diameter is obtained.